My first bike shop job in Austin showed me how many parts seize without grease. This isn't just about bikes, it's a basic rule for anything with threads or moving parts. I watch neighbors fight with stuck lawnmower wheels every spring, all from rust. A drop of grease or oil is cheap insurance against that kind of hassle. It's smart to learn this early and use it on all sorts of stuff around the house.
Absolutely preach this. My old commuter bike had a seatpost that basically became part of the frame, it was so stuck. Had to use a whole can of penetrating oil and a giant wrench, totally mangled the post. Now I grease everything, even the bolts on my kitchen table after it wobbled for months. That tiny bit of effort saves you from a massive fight later.
Struggled with a seized seatpost on my old mountain bike last summer. Spent what felt like forever twisting and pulling with no luck. My hands were sore and I almost gave up. Now I always put a little grease on the threads before installing anything. Your tip is so true, it saves so much time and frustration!